1. Field of the Invention
The present invention relates to a mask and a method for manufacturing a mask, to a method for manufacturing a display, to a method for manufacturing an organic electroluminescent display, to an organic electroluminescent device, and to an electronic device.
Priority is claimed on Japanese Patent Application No. 2003-386511, filed Nov. 17, 2003, the content of which is incorporated herein by reference.
2. Description of Related Art
In a manufacturing process of low molecular fill-color organic EL (electroluminescent) displays, for example, masks are used to pattern pixels of the display by evaporating organic materials for forming pixels of various colors. Japanese Unexamined Patent Applications, First Publication Nos. 2001-93667 and 2001-185350 disclose one example of a technology for patterning pixels by evaporating organic materials forming pixels of various colors.
The methodology disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-93667 uses a metal mask as a mask, and the materials to be evaporated are evaporated and deposited on a glass substrate, i.e., evaporation object (an object on which a material is evaporated), while making the metal mask to come in a close contact with the glass substrate using a permanent magnet. As the size of the metal mask increases with an increase in the size of a glass substrate, the difference in the coefficient of linear expansion between the metal mask and the glass substrate becomes significant. As a result, misalignment between through-holes (openings) provided in the metal mask and the evaporation object may occur, especially at the edges of the glass substrate. On the other hand, the methodology disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-185350 uses a silicon mask as a mask, and the difference in the coefficient of linear expansion between the mask and a substrate is smaller compared to the metal mask in this technique. However, the glass substrate cannot be made to come in a close contact with the silicon mask without a permanent magnet. Furthermore, as the sizes of the silicon mask and the glass substrate increase, the bending deformations (distortion deformation) of the silicon mask and the glass substrate become significant. As a result, it may be difficult to make the silicon mask come in a close contact with the glass substrate during evaporation, and evaporated particles (evaporation materials) which pass trough the through-holes provided in the silicon mask may reach the space between the silicon mask and the glass substrate, which makes a precise patterning difficult.